Surgically implanted orthopedic cables are for the purpose of retaining and positioning bones and bone portions within a patient to support the bones in a desired position and to permit healing to take place following surgery. Such surgical cables and wires are generally connected together by a crimp, which is crushable by crimping pliers for crimp retention. See for example, Songer et al. U.S. Pat. Nos. 4,966,600; 5,116,340; 5,536,270; and Kilpela et al. U.S. Pat. Nos. 5,415,658 and 5,649,927. Also, the Dall-Miles crimp is a crushable crimp having a pair of bores extending therethrough to receive cable or wire and to retain them when the crimp is crushed.
It is desirable to maximize the capability of crimps to be retained in a single, predetermined position against a bone after it has been applied to one or more cables, to hold the cable and crimp under tension in a predetermined position. It is also desirable for such a crimp to collapse with a decreased tool force, while at the same time retaining a highly efficient xe2x80x9choldxe2x80x9d of the crimp on the cable. Such crimps also desirably retain a low profile as they rest on the bone, in a manner described in the previously cited U.S. Pat. No. 5,649,927.
By this invention, a crimp is provided which exhibits the above advantages, for more effective surgical utility.
In accordance with this invention, a malleable metal crimp is provided for securing a plurality of wire or cable portions together, typically for securing bones together in a desired position as part of orthopedic surgery. The crimp defines a pair of separate, parallel bores extending through the crimp, to each receive a wire or cable portion. The crimp has a pair of opposed ends which each define a pair of circumferentially-spaced, outwardly projecting flanges which are respectively positioned on opposite sides of the crimp. Thus, the flanges may rest against the bone while providing spacing for jaws of crimping pliers between a central portion of the crimp and the bone. Thus, such a crimp may be tightly secured to tensioned cable with crushing to secure the cable (or wire) under the desired tension, without significant loss of tension after the crimping pliers are withdrawn.
Preferably, the flanges of the crimp each define at least one pointed tooth for engaging a bone, to resist slippage of the crimp relative to the bone. Typically, four pointed teeth are provided, one adjacent to each corner of the crimp.
It is also preferred for the crimp to carry a central, external groove, formed on the crimp parallel to the bores and between the crimp ends for the purpose of facilitating collapse of the crimp. Such grooves can allow a significantly decreased tool force required to successfully collapse the crimp and to secure it onto the cable or wire. Additionally, such grooves can provide more efficient holding of the cable or wire by the crimp after it has been collapsed.
Preferably, the flanges of the crimp each define a circumferential angle about the nearest bore to each respective flange of about 30 to 90 degrees. Also, the respective centers of the flanges (the point within the flange which, on balance, is farthest spaced from the edges of the flange) are each preferably positioned to one side of a plane which encloses both longitudinal axes of the bores. In other words, from an end view of the crimp, the flanges appear to be directed downwardly, toward the bone on which the flange rests in the typical position of use of the flange.
Additionally, special crimping pliers may be used for crushing the crimp of this invention and applying it into gripping relation on cable or wire. Such crimping pliers comprise a pivotally connected pair of handles, each of the handles connecting to one of a pair of interacting jaw portions at the end of each of the handles, to form a pliers jaw for crushing cable/wire crimps which are positioned between the interacting jaw portions. One or both of the jaw portions may be pivotally connected to the handles, in a known configuration for the design of crimping pliers.
By this invention, one of the jaw portions comprises a pair of sidewalls and spaced, crimp retaining prongs, which sidewalls define a crimp space between the retaining prongs. The other of the jaw portions defines a single crimp gripping and crushing prong, which is positioned to move toward the crimp space as the jaw portions are pivoted to a closed, crimp-crushing position. Specifically, the spacing of the pair of crimp retaining prongs and dimensions of the single crimp gripping and crushing prong may be such that the crimp gripping and crushing prongs can enter into the crimp space when the crimping jaws are closed.
It is preferable for the crimp-retaining prongs to define outer walls of a pair of transversely extending crimp retaining troughs, although, if desired, the pair of troughs may comprise sections of a single trough as an equivalent structure. The crimp space is preferably defined by a longitudinally extending trough in one of the jaw portions, which longitudinally extending trough extends rearwardly along the jaw portion beyond the crimp space, and which has a floor that is deeper than the floor or floors of the transversely extending crimp retaining troughs. This longitudinally extending trough may be sized to receive the other jaw, including the single, crimping and crushing prong or projection. Specifically, this other jaw, which is typically the upper jaw of the crimping pliers, may comprise a piece of a single plate which, in turn, defines the single crimp gripping and crushing prong or projection.
Thus a double bore crimp may be provided having a firmly retained position on a bone, which retention is resistant to lateral movement because of the presence of pointed teeth that engage the bone to resist slippage of the crimp. Furthermore, the crimp may be more easily crushed with lower crushing force exerted by crimping pliers or the like, while retention of wires and/or cables inserted in the bores may remain very strong and even may be improved.